It only just occurred to me that many people might think the whole "make up for the human companion's flaws" plot device in this story was just a convenient "author's out" so Chell would be able to learn things and talk more about herself. That's actually not the origin of that part of my story, though - that was actually my headcannon for what Companion Cubes could do before I even felt inspired to write a Portal fanfic in the first place.
It came from the Portal comic, in which Doug Rattman and his Companion Cube make some bold moves. Doug Rattman was psychotic, and was on anti-psychotic medications, which he saved for emergencies. Under normal circumstances, his Companion Cube spoke to him; when he took the pills, however, the Cube was rendered mute. There are a lot of theories behind that, but what I thought was that the Cube was designed to communicate effectively with a psychotic man, so when he was rendered no longer psychotic, the Cube's normal communication system could no longer communicate with him. Maybe different frequencies of sound or something else entirely was needed for the Cube's words to sound coherent to a deeply psychotic person. That was my idea, anyway. That led to the idea that Companion Cubes have to be specially designed to work with their human Companions - I mean, making adjustments to communicate with a person with a particular psychosis is pretty specific to one person, it couldn't be that all Cubes did that, only that one. And I'm not the first person to come up with "some form of robotic system calibrates to specifically work with one person when touched".
I was leaving it unsaid because I wanted people to figure it out on their own, but on further reflection, I realized a lot of people probably figured it was just a plot device shoehorned in for convenience's sake. It wasn't. This was a very late disclaimer, but here it is now. :P Anyway, now this story is really done.
